This application relates to electro-magnetic motors and generators, and more particularly to electro-magnetic drive systems for motors and generators.
The Archimedes"" screw, also known as an Archimedean screw or water screw, has been used for thousands of years as an efficient method of raising water. Believed to be the design and invention of Archimedes"" of Syracuse (circa 287-212 B.C.), these devices have been designed usually with one to 8 blades and powered by humans, animals, water, or electricity since that time by applying power to the center cylinder of the water screw. Typically, the normal course of driving an Archimedes"" screw is to power the rotor/central shaft forming the axis. However, some ancient drawings indicate a design where a water wheel is used to drive a gear that drives an Archimedes"" screw.
If energy and water crises are brought on by the continued growth and urbanization of the population, the need for more efficient pumps for fluids and solids, and for more efficient hydrogenation may become increasingly important. Moreover, there is currently a need to provide biologically friendly solutions to the use of our much-needed dams.
Currently, the use of inner cylinder driven Archimedes"" screws to lift water is gaining in popularity because of the biologically friendly nature of the device and its energy efficiency. At Red Bluff Calif., a crisis with the Winter Chinook Salmon required lifting the gates of the diversion dam (Red Bluff Diversion Dam, or RBDD) to facilitate the passage of the Winter Chinook to their breeding grounds. The DOI (Department of the Interior) had already instituted a fish ladder but, according to Max Stodolski of RBDD in an on-site conversation Jun. 18, 2001, the percentage of Salmon that used the fish ladder was insufficient to allow for the continued survival of the species in the Sacramento River. Most fish simply tried unsuccessfully to follow the scent of the water leaking through the gates and died a week or so later having been unsuccessful at breeding.
The DOI installed a facility to raise the water to acceptable levels and tested two large Archimedes"" screws to see if they would safely allow the passage of Salmon. The test results showed that less than 2% of the fish passed through the water screws died subsequently, even though they were first assessed, then forced into the water screws through a 12xe2x80x3 pipe, then screened, penned, separated, counted, and again assessed, all of which increases the likelihood of death. The DOI now accepts the concept that Archimedes"" screws are fish friendly.
In 1839 John Ericsson invented the xe2x80x9cscrewxe2x80x9d propeller for use on ships he was designing with steam engines. The power of the screw was recognized as an efficient way to translate the energy from the rotating shaft to propel the ship. The debut of the screw propeller on the USS Monitor and the subsequent success has made it one of the most enduring and useful inventions of mankind. The same, basic design is still being used at the beginning of the 21 st century. However, it is a truncated Archimedes"" screw without the outside cylinder, and rounded blades.
Implementations of the systems and techniques described herein may include various combinations of the following features.
In one aspect, an apparatus includes a rotor defining a helical internal chamber, a plurality of magnets coupled with the rotor to create a magnetic field surrounding the rotor, and a housing surrounding the rotor, the housing having a variable electro-magnetic force element immersed in the magnetic field. The rotor may include a cylindrical portion containing a screw having a thread that extends laterally entirely to an inner wall of the cylindrical portion and longitudinally for a full length of the cylindrical portion. The cylindrical portion need not reach the full length of the rotor. The screw may have multiple threads or blades. The apparatus may also include one or more bearings, where a first portion of each bearing may be retained by the rotor and a second portion of each bearing may be retained by the housing.
The apparatus may also include a spacer coupled between the rotor and the plurality of magnets such that the plurality of magnets are coupled with the rotor through the spacer. The spacer may be a solid ring coupled with an exterior surface of the rotor. Alternatively, the spacer may be a lattice coupled with an exterior surface of the rotor. The spacer may be designed for thermal reasons, structural reasons such as those related to the materials used in the rest of the apparatus, mechanical reasons such as spacing to fit a particular structural design, and/or electromechanical reasons such as those related to power requirements.
The plurality of magnets may be oriented perpendicular to the rotational axis of the rotor. Alternatively, the plurality of magnets may be oriented parallel to the rotational axis of the rotor. The stator may be cast metal, one or more printed circuit boards, or wire windings. The variable electro-magnetic force element may be wire windings. The apparatus may be used in many different applications, including as a pump/generator/fish ladder for a dam, as a drive system for a boat or ship, as a vortex generator for wind generation systems, as a fan to move gaseous mater, or to move liquids or solids. Many materials may be used to construct the housing as well as the rotor depending upon the particular application and associated engineering requirements.
In another aspect, a system includes a rotor that includes an Archimedean screw and a plurality of magnets, and a stator rotatably coupled with the rotor, wherein the rotor resides inside the stator. The Archimedean screw may have more than one blade. The rotor may include a spacing structure, the Archimedean screw may be coupled with the spacing structure, and the plurality of magnets also may be coupled with the spacing structure, such as a lattice connecting an exterior surface of the Archimedean screw with the magnets. The plurality of magnets may be axially magnetized permanent magnets oriented in a parallel arrangement. The rotor may include a first end and a second end that are both submerged in a liquid, such as when the system is used as a generator in a dam. Moreover, the system may include end caps to prevent loss of magnetism to a surrounding area.
In yet another aspect, a method of using an Archimedes"" screw includes using the energy from a flowing fluid to rotate the rotor, capturing induced magnetic flux using an electro-magnetic force element, and generating energy from the captured induced magnetic flux. A fluid can be allowed to pass through a rotor comprising an Archimedes"", screw, magnetic flux can be captured using an electro-magnetic force element, the magnetic flux being induced by motion of the rotor resulting from the passing fluid, and energy can be generated from the captured induced magnetic flux. Energy may be periodically used to reverse a flow of the fluid passing through the Archimedes"" screw to pump the fluid back through the Archimedes"" screw.
The fluid may be water. Energy may be periodically used to slow a flow of the water to allow fish to pass through the Archimedes"" screw, which may be coupled with a dam, against the flow. Allowing the fluid to pass may involve allowing suspended solids to pass through the rotor to provide on-going sediment flushing.
Alternatively, the fluid may be atmospheric air, and the method may further involve driving the air using the Archimedes"" screw to create a vortex before using the generated vortex to drive the Archimedes"" screw to generate power from the captured induced magnetic flux.